SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.emulator.vm;

import cc.squirreljme.runtime.cldc.debug.Debugging;
import cc.squirreljme.vm.VMClassLibrary;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import net.multiphasicapps.collections.IdentityMap;

/**
 * This is a suite manager which merges multiple suite managers into one so
 * that more libraries from different sources may be included.
 *
 * @since 2018/12/08
 */
public final class MergedSuiteManager
    implements VMSuiteManager
{
    /** The source managers. */
    private final VMSuiteManager[] _sources;
    
    /** The library to ID mapping. */
    private final Map<VMClassLibrary, Integer> _libToId =
        new IdentityMap<>(new LinkedHashMap<>());
    
    /** The next library ID. */
    private volatile int _nextLibId;
    
    /**
     * Initializes the merged suite manager.
     *
     * @param __s The sources to use.
     * @throws NullPointerException On null arguments.
     * @since 2018/12/08
     */
    public MergedSuiteManager(VMSuiteManager... __s)
        throws NullPointerException
    {
        if (__s == null)
            throw new NullPointerException("NARG");
        
        // Defensive copy and check for nulls
        __s = __s.clone();
        for (VMSuiteManager s : __s)
            if (s == null)
                throw new NullPointerException("NARG");
        
        this._sources = __s;
    }
    
    /**
     * {@inheritDoc}
     * @since 2023/12/18
     */
    @Override
    public int libraryId(VMClassLibrary __lib)
        throws IllegalArgumentException, NullPointerException
    {
        if (__lib == null)
            throw new NullPointerException("NARG");
        
        Map<VMClassLibrary, Integer> libToId = this._libToId;
        synchronized (libToId)
        {
            Integer rv = libToId.get(__lib);
            if (rv == null)
                throw new IllegalArgumentException(
                    "Unknown library: " + __lib);
            
            return rv;
        }
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/12/08
     */
    @Override
    public final String[] listLibraryNames()
    {
        Set<String> rv = new LinkedHashSet<>();
        
        // Add libraries that exist, but do not duplicate them!
        for (VMSuiteManager m : this._sources)
            for (String s : m.listLibraryNames())
                rv.add(s);
        
        return rv.<String>toArray(new String[rv.size()]);
    }
    
    /**
     * {@inheritDoc}
     * @since 2018/12/08
     */
    @Override
    public final VMClassLibrary loadLibrary(String __s)
        throws NullPointerException
    {
        if (__s == null)
            throw new NullPointerException("NARG");
        
        // Go through the libraries and see if any exist
        for (VMSuiteManager m : this._sources)
        {
            VMClassLibrary rv = m.loadLibrary(__s);
            if (rv != null)
            {
                // Do we need to initialize a library ID here?
                Map<VMClassLibrary, Integer> libToId = this._libToId;
                synchronized (libToId)
                {
                    if (!libToId.containsKey(rv))
                        libToId.put(rv, ++this._nextLibId);
                }
                
                // Use it
                return rv;
            }
        }
        
        // Not found
        return null;
    }
}